1 /*
2 * w1_therm.c
3 *
4 * Copyright (c) 2004 Evgeniy Polyakov <johnpol@2ka.mipt.ru>
5 *
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the therms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 */
21
22 #include <asm/types.h>
23
24 #include <linux/kernel.h>
25 #include <linux/module.h>
26 #include <linux/moduleparam.h>
27 #include <linux/device.h>
28 #include <linux/types.h>
29
30 #include "w1.h"
31 #include "w1_io.h"
32 #include "w1_int.h"
33 #include "w1_family.h"
34
35 MODULE_LICENSE("GPL");
36 MODULE_AUTHOR("Evgeniy Polyakov <johnpol@2ka.mipt.ru>");
37 MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol, temperature family.");
38
39 static u8 bad_roms[][9] = {
40 {0xaa, 0x00, 0x4b, 0x46, 0xff, 0xff, 0x0c, 0x10, 0x87},
41 {}
42 };
43
44 static ssize_t w1_therm_read_name(struct device *, char *);
45 static ssize_t w1_therm_read_temp(struct device *, char *);
46 static ssize_t w1_therm_read_bin(struct kobject *, char *, loff_t, size_t);
47
48 static struct w1_family_ops w1_therm_fops = {
49 .rname = &w1_therm_read_name,
50 .rbin = &w1_therm_read_bin,
51 .rval = &w1_therm_read_temp,
52 .rvalname = "temp1_input",
53 };
54
55 static ssize_t w1_therm_read_name(struct device *dev, char *buf)
56 {
57 struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
58
59 return sprintf(buf, "%s\n", sl->name);
60 }
61
62 static inline int w1_convert_temp(u8 rom[9])
63 {
64 int t, h;
65
66 if (rom[1] == 0)
67 t = ((s32)rom[0] >> 1)*1000;
68 else
69 t = 1000*(-1*(s32)(0x100-rom[0]) >> 1);
70
71 t -= 250;
72 h = 1000*((s32)rom[7] - (s32)rom[6]);
73 h /= (s32)rom[7];
74 t += h;
75
76 return t;
77 }
78
79 static ssize_t w1_therm_read_temp(struct device *dev, char *buf)
80 {
81 struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
82
83 return sprintf(buf, "%d\n", w1_convert_temp(sl->rom));
84 }
85
86 static int w1_therm_check_rom(u8 rom[9])
87 {
88 int i;
89
90 for (i=0; i<sizeof(bad_roms)/9; ++i)
91 if (!memcmp(bad_roms[i], rom, 9))
92 return 1;
93
94 return 0;
95 }
96
97 static ssize_t w1_therm_read_bin(struct kobject *kobj, char *buf, loff_t off, size_t count)
98 {
99 struct w1_slave *sl = container_of(container_of(kobj, struct device, kobj),
100 struct w1_slave, dev);
101 struct w1_master *dev = sl->master;
102 u8 rom[9], crc, verdict;
103 int i, max_trying = 10;
104
105 atomic_inc(&sl->refcnt);
106 if (down_interruptible(&sl->master->mutex)) {
107 count = 0;
108 goto out_dec;
109 }
110
111 if (off > W1_SLAVE_DATA_SIZE) {
112 count = 0;
113 goto out;
114 }
115 if (off + count > W1_SLAVE_DATA_SIZE) {
116 count = 0;
117 goto out;
118 }
119
120 memset(buf, 0, count);
121 memset(rom, 0, sizeof(rom));
122
123 count = 0;
124 verdict = 0;
125 crc = 0;
126
127 while (max_trying--) {
128 if (!w1_reset_bus (dev)) {
129 int count = 0;
130 u8 match[9] = {W1_MATCH_ROM, };
131 unsigned long tm;
132
133 memcpy(&match[1], (u64 *) & sl->reg_num, 8);
134
135 w1_write_block(dev, match, 9);
136
137 w1_write_8(dev, W1_CONVERT_TEMP);
138
139 tm = jiffies + msecs_to_jiffies(750);
140 while(time_before(jiffies, tm)) {
141 set_current_state(TASK_INTERRUPTIBLE);
142 schedule_timeout(tm-jiffies);
143
144 if (signal_pending(current))
145 flush_signals(current);
146 }
147
148 if (!w1_reset_bus (dev)) {
149 w1_write_block(dev, match, 9);
150
151 w1_write_8(dev, W1_READ_SCRATCHPAD);
152 if ((count = w1_read_block(dev, rom, 9)) != 9) {
153 dev_warn(&dev->dev, "w1_read_block() returned %d instead of 9.\n", count);
154 }
155
156 crc = w1_calc_crc8(rom, 8);
157
158 if (rom[8] == crc && rom[0])
159 verdict = 1;
160
161 }
162 }
163
164 if (!w1_therm_check_rom(rom))
165 break;
166 }
167
168 for (i = 0; i < 9; ++i)
169 count += sprintf(buf + count, "%02x ", rom[i]);
170 count += sprintf(buf + count, ": crc=%02x %s\n",
171 crc, (verdict) ? "YES" : "NO");
172 if (verdict)
173 memcpy(sl->rom, rom, sizeof(sl->rom));
174 else
175 dev_warn(&dev->dev, "18S20 doesn't respond to CONVERT_TEMP.\n");
176
177 for (i = 0; i < 9; ++i)
178 count += sprintf(buf + count, "%02x ", sl->rom[i]);
179
180 count += sprintf(buf + count, "t=%d\n", w1_convert_temp(rom));
181 out:
182 up(&dev->mutex);
183 out_dec:
184 atomic_dec(&sl->refcnt);
185
186 return count;
187 }
188
189 static struct w1_family w1_therm_family = {
190 .fid = W1_FAMILY_THERM,
191 .fops = &w1_therm_fops,
192 };
193
194 static int __init w1_therm_init(void)
195 {
196 return w1_register_family(&w1_therm_family);
197 }
198
199 static void __exit w1_therm_fini(void)
200 {
201 w1_unregister_family(&w1_therm_family);
202 }
203
204 module_init(w1_therm_init);
205 module_exit(w1_therm_fini);
206
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